When operating a diesel engine in cold weather, for example on a heavy duty truck, a commonly encountered problem is the congealing of fuel due to the crystallization of wax contained in the diesel. The crystallized wax particles can plug fuel filters, and cause uneven firing, loss of power, excessive vibration, stalling and eventual engine shutdown. If the temperature is low enough, diesel fuel can congeal in the fuel line sufficiently to prevent an engine from starting.
One method for relieving this problem is to provide heat tape within a fuel line, as described in U.S. Pat. No. 4,372,279, assigned to Paccar Inc, the assignee of the present application. This design is not completely satisfactory, however, given that some congealing may still occur upstream of the heat tape. Also, in some situations, the temperature of the fuel being sent to the engine may exceed the specifications of engine manufacturers.
A need therefore exists for an improved system for heating fuel lines.